Consensus needed on benefit of 16-bit editing

Dan Margulis questions editing Photoshop files using 16-bit in his new book: “Photoshop LAB Color: The Canyon Conundrum and Other Adventures in the Most Powerful Colorspace”

In Chapter Six of the book he argues that even though high bit editing sounds sensible, in practice the theory doesn’t work. On images containing computer generated gradients, yes. But on color photographs, no. “In the last three years, around a dozen people, including me, have made serious efforts to find anything to support the proposition that 16-bit editing might be better under any circumstances. … nobody has found any quality gain at all.”

“At this point the evidence is overwhelming that there is no 16-bit advantage in dealing with color photographs. A few people argue otherwise, but it has now become a matter of religious belief, rather than reliance on demonstrations that they can't provide”.

This is a very important issue for all of us that use Photoshop.  Many of us now keep multi-layered files as 16-bit until we are ready to print. I have 10,000 files like this and I don’t want to double my storage requirements and slow my processing time by using 16-bit unless there is clearly a benefit. We need a definitive answer.

Please offer your opinion and back it up with evidence.
Thank you!
Yours truly,
Henry F. Domke
Henry Domke Fine Art
http://www.henrydomke.com

I am trying to get you, the experts to agree on this. I am posting this same question to:
Michael Reichmann: http://www.luminous-landscape.com
Tom Hogan: http://www.bythom.com
Tim Grey: http://www.timgrey.com
Adobe Expert Help: http://www.adobe.com/support/expert_support/main.html
Adobe Photoshop Forum: http://www.adobe.com/support/forums/main
Ron Galbrith: http://forums.robgalbraith.com
Phil Askey: http://www.dpreview.com
Bruce Fraser: http://www.creativepro.com
Stephen Johnson: http://www.sjphoto.com
Bill Atkinson: http://www.billatkinson.com
Katrin Eismann: http://www.photoshopdiva.com
Martin Evening: http://www.martinevening.com
Andrew Rodney: http://www.digitaldog.net
Dan Margulis: http://groups.yahoo.com/group/colortheory